CactusTest/TestArray outputs unitialized data for gf4d

the current test arrays in CactusTest/TestArrays does not initialize the 4d array that it outputs. The data in the test output files apparently ended up being zero in the past but gives me poison on my machine right now.

The attached patch adds the required code to fill in the 4d array the same way that the 0d-3d arrays are filled in.

The patch calls
CCTK_GrouplbndGI(ierr,cctkGH,4,lbnd_4d,groupindex3)
in a few places. Shouldn't it be groupindex4? Similarly 'varindex3'.
Fixed. Thank you for spotting this.

Also, just minor, could line 316:
& (lbnd_4d(3)+k)*(lbnd_4d(4)+m)
be lined up such that these terms align with the ones on the previous line?
Yes, in principle it should be. I have modifid the patch to mirror the alignement of the 3d grid function loop which aligns the "(" with the "i" of the line above. This was what I had initially intended but was off by one space.